Incidence of oesophageal and stomach cancer as related to nitrate-N concentration in groundwater in Jaffna Peninsula

Abstract

This study focused on assessment of the risk association between cancer and consumption of drinking water with high nitrate-N in three selected areas in Jaffna peninsula. Based on the available patients' data sheets in Jaffna leaching hospital, three areas namely Vadamaradchchi, Chunnakam and Jaffna were selected for this study during the period from December 2010 to April 2011. Ten wells from each area were selected of households with cancer patients (case) and other thirty wells from households with no cancer patients (control) in their families. A questionnaire was used to collect data for analysis of exposure parameters and relative risk for cancers. Out of the total affected population with oesophagus and stomach cancers, 54% were males and 46% were females, Further it was found that Chunnakam area is significantly different (P<0.05) from the other two areas with respect to nitrate-N concentration in well water. Since, the odds ratio for Chunnakam area was greater than 1 there is a risk for cancer due to drinking well-water with higher nitrate-N concentration than the recommended level of WHO. Relative risk values were greater than 1 at all of the three selected areas and it explains that there is a health risk due to drinking water with nitrate-N concentrations higher than the recommended level. However, there was no evidence to support the significant correlation between nitrate-N concentration in well water and incidences of cancers in the study area.